Distribution, sources and potential health risks of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected during different monsoon seasons and haze episode in Kuala Lumpur

This study aimed to determine the distribution and potential health risks of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected in Kuala Lumpur during different monsoon seasons. The potential sources of PM2.5 were investigated using 16 priority PAHs with additional of biomass tracers namely levoglucosan (LV), mannosan (MN) and galactosan (GL). This study also investigated the cytotoxic potential of the extracted PAHs towards V79-4 cells. A high-volume air sampler (HVS) was used to collect PM2.5 samples for 24 h. PAHs were extracted using dichloromethane (DCM) while biomass tracers were extracted by a mixture of DCM/methanol (3:1) before analysis with gas chromatography-mass spectrometry (GC-MS). The cytotoxicity of the PAHs extract was determined by assessing the cell viability through the reduction of tetrazolium salts (MTT). The results showed that the total mean ± SD concentrations of PAHs during the southwest (SW) and northeast (NE) monsoons were 2.51 ± 0.93 ng m-3 and 1.37 ± 0.09 ng m-3, respectively. Positive matrix factorization (PMF) using PAH and biomass tracer concentrations suggested four potential sources of PM2.5; gasoline emissions (29.1%), natural gas and coal burning (28.3%), biomass burning (22.3%), and diesel and heavy oil combustion (20.3%). Health risk assessment showed insignificant incremental lifetime cancer risk (ILCR) of 2.40E-07 for 70 years of exposure. MTT assay suggested that PAHs extracts collected during SW monsoon have cytotoxic effect towards V79-4 cell at the concentrations of 25 μg mL-1, 50 μg mL-1, 100 μg mL-1 whereas non-cytotoxic effect was observed on the PAHs sample collected during NE monsoon.